Windows won't start up

I am repairing a friends Dell Dimension 5100, WinXP sp3 1G ram, it hangs on bootup in any configuration, (safe, regular, past good config) sometimes it will get to the two tone blue startup with accounts shown. You can click on a account but it won't load past that. The Safe mode only goes to the black screen. I did get it to start up fully, "once" and I was in the process of clearing 11 programs running on start-up. when it asked for reboot. I think the program I was shutting down was Mcafee. It has not started right since. Also I should mention the HD is an 80G (71 actual) and it is 54g full (3/4 full). I am sure it has a ton of adware/malware, maybe not a lot of virus's as mcafee was running.
How do I get this to run so I can fix it?

 

I got it to start in safe mode, I am removing Mcafee. and transfereing stored files to another computer. once I get to below half full I may be able to run in normal mode and De-Malware it.

 

Do you get any blue screens of death for even a fraction of a second before rebooting?

 

No I didn't get any blue screens. It is running in safe mode "finally" and I am deleteing progs and AV's, Yes there were two AV's, and about 30g of games and prog's.

Thanks for your reply, I'll keep ya posted on how it went. Next I'll be back on Major Geek Malware forum with this puters stuff. I already have the other puters logs there now, no reply yet on those logs.